Two-stage liquefied petroleum gas dispensing system



Jan. 25, 1949. L. J. WHITE 2,450,158

TWO-STAGE LIQUEFIED PETROLEUM GAS DISPENSING SYSTEM Filed March 13, 1945 I N VEN TOR.

L. JWhiie.

A TTdHNEY.

Patented Jan. 25, 1949 TWO-STAGE LIQUEFIED PETROLEUM GAS DISPENSING SYSTEM Loyd J. White, San Antonio,

Steel Company, San Antonio, Tex.,

Southern a corporation of Texas Application March 13, 1945, Serial No. 582,450

7 Claims.

This invention relates to apparatus for dispensing liquefied petroleum gas, such as mixtures of commercial butane and propane and, among other objects, aims to provide an underground system of the two-stage pressure reduction type having a greatly simplified and improved vaporizer for the fuel between the pressure reducers or regulators. The main idea is to provide a compact. factory-assembled system incorporating an eflicient fuel vaporizer which forms a part of a protecting casing extending upwardly from the usual pressure storage container or tank to a point above the ground level.

Another aim is to provide a system of this type designed to supplant two-stage systems of the general type shown in my copending application, Ser. No. 237,113, filed October 26, 1938.

A still further aim is to provide important improvements in the general type of underground system disclosed in my Patent No. 2,260,356, dated October 28, 1941.

Other aims and advantages of the. invention will appear in the specification, when considered in connection with the accompanying drawing, wherein:

The figure is a side elevation, partly in section. of an underground system embodying the invention.

Referring more particularly to the drawing, the illustrated embodiment of the invention is designed to increase the vaporizing capacity of an ordinary two-stage pressure reduction system of the general type disclosed in my Patent No. 2,176,829, dated October 1'7, 1939. Such systems are designed to insure the delivery of gas of a uniform B, t. u. content from a mixture of liquefied petroleum gases, such as ordinary commercial butane and propane. In the type of system disclosed in my aforesaid copending application, the educted fuel, after it passes through a first stage pressure reducing regulator, has to be completely vaporized before it passes through a second stage pressure reducing regulator. The latent heat of vaporization for the residual liquid which passes through the first stage regulator, has to be supplied by the fuel contents of the storage container. When the liquid fuel in the storage container is nearly exhausted, the supply of heat to the submerged vaporizer is greatly reduced. Hence, such a system does not have a uniform vaporizing capacity. This invention is, therefore, designed to overcome this difficulty and to provide, as a part of a factory-assembled system, a large vaporizer incorporated within a protecting casing extending from the tank to a point above ground, where the appurtenances are accessible from above the ground for servicing the container.

In the present example, an underground pressure storage container or tank III is shown as Oil Tex., asslgnor to having a standpipe i I connected thereto and carrying a valved filling and dispensing fitting l2 at its upper end. This fitting may be generally like that shown in my Patent No. 2,176,829. A liquid eduction pipe 13 extends downwardly from the fitting to the bottom portion of the storage container and the arrangement is such that educted liquid passes through a valved outlet nipple l4 carried by the fitting. In this instance, an ordinary liquid level gage ii of the float type is shown as being connected to the fitting; although it is to-be understood that other forms of gages may be employed. Such fittings and appurtenances are well known in the art and require no further description.

In the present example, the tank Ill is shown as being buried in the ground below the frost line and it has a cylindrical casing or housing 16 welded to its upper side, as shown at ll, to provide a liquid-tight compartment. This casing is somewhat larger than the ordinary protecting casings employed in the systems of the general type shown in my aforesaid Patent No, 2,260,356. It extends above the ground level and has a hinged cover or closure l8 to afford access to the fitting and other appurtenances within the upper end of the casing. As will be seen, the standpipe ll extends upwardly through the central portion of the casing and a head i9. which is shown as being dished downwardly, is welded therein at a point near the ground level, to provide a closed vaporizing chamber 20, wherein the liquid fuel is adapted to be vaporized.

The liquid which passes through the valved fitting is delivered through a first stage pressure reducing regulator 2|; thence through a tube 22 into the upper portion of the chamber 20. A portion of the liquid is flashed into vapor due to the contained heat and the pressure reduced to about 5 to 10 pounds. It will be understood that the pressure in the tank will vary from, say, 20 to 40 pounds, depending upon the underground temperature. In this example, the residual liquid is shown as being discharged from the end of the tube 22 into a spiral trough 23 conveniently tack-welded to the inside wall of the casing and leading downwardly to a point near the bottom. This trough member can be of any convenient shape, but is shown as being made of bent structural angle. The idea is to increase the heat absorbing capacity of the casing and also to expose a large surface of the residual liquid to vaporization as it runs around the trough, so that it will be completely vaporized before it reaches the bottom of the chember2ll.

As has already been stated, a portion of the educted liquid is flashed into vapor as it enters the chamber through the tube 22. That portion of the vapor will be separated from the liq- 3 uid in the trough and, as the residual liquid is vaporized, it will combine with the flashed vapor. Thus. the chamber acts as a combined separator and vaporizer, wherein the pressure is maintained by the first stage pressure reducing Further to increase the heat absorption of the vaporizer. the cylindrical casing is shown as having vertical heating fins 24 which are generally triangular shaped and preferably made of sheet metal of good heat conductivity. These fins are in the form 01 bracing wings which are welded to the opposite side walls oi the casing II and to the top wall of the tank. Also, they are shown as having hook openings 2| near their upper ends to facilitate handling the system with an auto crane or hoisting mechanism. The vapor is delivered from the chamber II through a tube 26 and a second stage regulator 21 which reduces the pressure to, say, about six ounces for use in gas consuming appliances. A service pipe 28 is connected to the second stage pressure reducing regulator and is shown as having a vertical run suitably secured against one of the heating fins by means of ordinary clips so. However, that the service pipe may extend downwardly within the vaporizing the bottom part of the vaporizing tank and then extend outwardly therethrough. Furthermore, it will be understood that the service pipe may have an underground re-vaporizer at its low point, similar to that shown in my Patent No.

2,105,383. However, it forms no part of the present invention.

From the foregoin description. it will be understood that the system is very compact in its design and can be factory-assembled and shipped without damage. There are no protruding or separate parts subject to breakage or loss. The valve fitting and the pressure regulators are nested within the upper end portion of the easing or housing and can conveniently be covered up with insulating material (not shown) during extremely cold weather. The casing is made sumciently large to take care of the normal demand on such a system without depending upon absorption of heat from the liquid contents of the main storage tank. Heat will be absorbed by all metal parts b ried in the ground and will be conducted upwardly through the metal to and through the wall of the casing i6. Moreover,

it it is desired further to increase the sensible heat within the chamber 20, metal shavings of high heat conductivity may be packed in the chamber -to expose a maximum surface of residual liquid to vaporization.

Obviously, the invention is not restricted to the particular embodiment thereof herein shown and described.

What is claimed is:

1. A liquefied petroleum gas system of the liquid eduction type, comprisin in combination, an underground pressure storage container adapted tube charged with a mixture oi butane and propane: a standpipe connected to the container and carrying filling and liquid dispensing means; a protecting casing for the standpipe connected to the container; 9. met stage pressure reducer connected to receive the educted liquid; a gas-tight vaporizin compartment formed by the lower portion of said casing with the container constituting the bottom wall thereof and connected to the first stage pressure reducer to vaporize residual liquid discharged therefrom by heat exchange with the container;

vaporizing ber Arranged todeliverthevaporatservlcepressurei'eruscinso:

mmgapplianoes. v

- p ,7 pctrolcumgassy'stemoitheliquid V uction type," lneombination, an underground storage container adapted to be charged with a mixture 0! butane and propane: a standpipe connected to the container and carrying filling and liquid means; a protecting casing for the standpipe connected to the container; a first stage pressure rcducer connected to receive the educted liquid: said casing having apartition below its upper end providing a combined expansionchamber and vaporizer immediately above the tank and her and arranged to deliver vapor at service pressure for use in gas consuming appliances.

3. A liquefied petroleum gas system. as set forth in claim 1, wherein said protecting casing is welded to the storage container and said chamber is formed in the lower portion thereof above the storage contain 4. A liquefied petroleum Ias system, of the type set forth in claim 1, wherein the vaporizer constitutes a major portion or the protecting casing'and a spiral trough is arranged therein to receive residual liquid discharged from the ilrst stage pressure reducer.

5. A liquefied petroleum gas system, of the type set forth in claim I, wherein heat conducting this in the form of sheet metal plates are welded to the casing and to the upper side of the storage 6. In a liquefied petroleum gas system of the character described, having an underground pressure storage container, at protecting casing above the container iorming a vaporizing and expansion chamber; a liquid eduction pipe communicating with the bottom portion oi the container; a iirst stage pressure reducing regulator within the casing connected to receive ed liquid and discharge it into the vaporizing chamber; a second stage pressure reducing resulator connected to receive vapor from the chamber and discharge it to a service pipe: and heat exchanging fins connected to the casing and the container and he openings for hoisting mechanism arranged in their upper end portions; 7

'l. A liquefied tank and its upper end; era are nested within the casing adjacent to means.

and the pressure reducthe upper end portion oi the sum: and dispensing LOYD J. WHITE. RIiFEImNCEB CITED The following, references are oi record in the file of this patent:

Dec. 30, 194! the educt- 

